EP 0418808 A3 19911211 - MAGNETIC DISPERSIONS OF RARE EARTH MAGNETIC PARTICLES WITH HIGH MAGNETIC ENERGY PRODUCT IN FLEXIBLE HIGHLY SATURATED NITRILE RUBBER AND METHODS OF PROCESSING THE SAME
Title (en)
MAGNETIC DISPERSIONS OF RARE EARTH MAGNETIC PARTICLES WITH HIGH MAGNETIC ENERGY PRODUCT IN FLEXIBLE HIGHLY SATURATED NITRILE RUBBER AND METHODS OF PROCESSING THE SAME
Publication
Application
Priority
US 40953989 A 19890919
Abstract (en)
[origin: EP0418808A2] A flexible magnetic blend composition is provided which is comprised of high energy rare earth magnetic particles in a flexible high temperature resistant and oil resistant polymer binder. The binder system preferably comprises a highly saturated nitrile rubber (HSN) or a polymer alloy of the same in which a HSN is the major polymer and also contains additives which are compatible with processing, subsequent electron beam curing, and final product performance. The binder system is highly loaded, usually from about 50 to about 70 volume percent, with the high energy rare earth magnetic particles, which can produce bonded magnets with a maximum energy product of at least 2.5 megagauss-oersteds, a remenance, Br of at least 3400 gauss, a coercive force, Hc, of at least 2900 oersteds and an intrinsic coercivity, Hci, of at least 5000 oersteds. The process for production of this system involves the binder system and rare earth magnetic particles being mixed and then formed into a final geometry before being cured by high voltage electron beam radiation. The electron beam curing in the solid state fixes dimensional stability, magnetic properties, and oil, solvent and chemical resistance of the part even when exposed to subsequent hostile temperature environments of 100<o>C or higher. Further, the HSN binder system reduces oxidation of the rare earth magnetic particles from subsequent hot air aging when compared to conventional nitrile elastomer binder systems. Any off geometry parts or trim produced in the process prior to radiation curing can be recycled through processing several times without fear of premature cure.
IPC 1-7
IPC 8 full level
C22C 38/00 (2006.01); C08K 3/08 (2006.01); H01F 1/053 (2006.01); H01F 1/14 (2006.01)
CPC (source: EP US)
C08K 3/08 (2013.01 - EP US); H01F 1/0533 (2013.01 - EP US); C08K 2201/01 (2013.01 - EP US)
Citation (search report)
- [A] EP 0281295 A2 19880907 - ICI PLC [GB], et al
- [A] US 4664723 A 19870512 - ISHII JUNICHI [JP], et al
- [A] PATENT ABSTRACTS OF JAPAN, vol. 12, no. 423 (E-680)[3270], 9th November 1988; & JP-A-63 160 212 (MATSUSHITA ELECTRIC WORKS LTD) 04-07-1988
Designated contracting state (EPC)
AT BE CH DE DK ES FR GB GR IT LI LU NL SE
DOCDB simple family (publication)
EP 0418808 A2 19910327; EP 0418808 A3 19911211; CA 2025576 A1 19910320; JP H03205802 A 19910909; MX 166376 B 19930105; US 5051200 A 19910924
DOCDB simple family (application)
EP 90117921 A 19900918; CA 2025576 A 19900918; JP 24763390 A 19900919; MX 2244990 A 19900918; US 40953989 A 19890919